CA3046126A1 - Shaping equipment and facility for gas-phase chemical infiltration of fibrous preforms - Google Patents

Abstract

The invention relates to shaping equipment (100) for chemical vapour infiltration of a fibrous preform, comprising a structural enclosure formed by supports (140, 170) which are each provided with a multiperforated zone (141; 171). The supports (140, 170) comprise, on the inner face thereof, an unenclosed area (143; 173) including the multiperforated zone. The shaping equipment (100) also comprises first and second functional elements of a shaping mould (120, 150), each one being respectively present in the unenclosed area of the supports. Each functional element of the shaping mould has a first face (120a; 150a) having a determined shape corresponding to the shape of a part to be produced, and a second face (120b; 150b) held such that it faces the inner face of a support. Each functional element comprises a plurality of perforations (121; 151) and the number of perforations, the size of perforation or the geometry of perforation are different from the number, size or geometry of the perforations present on the facing support.

Description

1 "
Conformation tools and installation for infiltration chemical vapor phase of fibrous preforms Background of the invention The present invention relates to the production of parts made of composite material and, more particularly, conformation tooling used during consolidation and / or densification by chemical infiltration in the gas phase of a fiber preform intended to form the reinforcement of the composite material part.
A field of application of the invention is that of the embodiment of parts made of thernnostructural composite material, that is to say in composite material having both mechanical properties which the make it fit to form structural parts and the ability to keep these properties up to high temperatures. Examples typical of thermostructural composite materials are composites carbon / carbon (C / C) having a carbon fiber reinforcement texture densified by a pyrolytic carbon matrix and the composites to ceramic matrix (CMC) having a fiber reinforcement texture refractories (carbon or ceramic) densified by a ceramic matrix.
A well known process of consolidation or densification of fibrous preforms for making composite C / C or CMC parts is chemical vapor infiltration (CVI). Fibrous preforms to consolidate or densify are placed in a conformation tool multiperforated itself placed in a reactor or furnace where it is heated. A
reactive gas containing one or more gaseous precursors of the material constituent of the matrix is introduced into the reactor. The temperature and the pressure in the reactor are set to allow the reactive gas to diffuse within the porosity of the preforms via the perforations of the shaper and to form a deposit of the material constituting the matrix by decomposition of one or more constituents of the reactive gas or reaction between several constituents, these constituents forming the precursor of the matrix. An interphase material can be furthermore deposited with the matrix by this method.
However, this consolidation / densification technique leads in some cases to the appearance of matrix deposition gradients in the direction of the thickness of the fibrous preform as well as

2 local overthicknesses or pustules on the surface of the preform. Indeed, between the surface and the heart of the preform, the thickness or quantity of deposited matrix can vary by a factor of 5. These disadvantages are mainly due to a mismatch between the characteristics of the fiber preform (thickness of the preform, nature of the fibers, weave of weaving, etc.) and the structural characteristics of the shaper (number perforations, size and shape of perforations, etc.).
Object and summary of the invention The object of the invention is therefore to provide a solution for conformation tools with structural characteristics can be defined according to the fiber preform to be consolidated and / or densify.
This goal is achieved with a conformation tooling for the chemical vapor infiltration of a fibrous preform, the tooling comprising a structural enclosure formed of at least a first support having a first multiperforated zone surrounded by a first plane of contact and a second support comprising a second multiperforated zone surrounded by a second contact plane, the first and second supports being held against each other at level of the first and second contact areas, characterized in that the first support has on its inner face a first zone disbursed including the first multiperforated zone, in that the second support has on its inner face a second zone disbursed including the second multi-perforated zone, and in that the tooling of conformation further comprises at least first and second conformation mold functional elements present respectively in the first and second disbursed areas of the first and second supports, each conformation mold functional element having a first face having a corresponding determined shape to a form of part to be made and a second face maintained vis-à-screw of the inner face of a support, each mold functional element having a plurality of perforations and having at least one minus a number of perforations or a size of perforations or a perforation geometry different from the number, size or geometry of the perforations present on the support vis-à-vis.

3 Thus, the conformation tooling according to the invention comprises functional elements of mold of conformation conformation whose size, the number and / or geometry of the perforations can be defined in function of the characteristics of the fiber preform to be consolidated or densify in order to obtain a matrix and / or interphase deposit more homogeneous in the preform considered. It is thus possible to manufacture composite material parts having mechanical properties improved.
The conformation tooling of the invention has a large flexibility of adaptation while limiting the cost of this adaptation. In effect, in case of adaptation of the conformation tooling to a preform particular fibrous, only the functional elements of mold of conformation are changed, the main part of the tooling, namely the supports forming the structural enclosure, being preserved.
According to a first characteristic of the tooling of conformation of the invention, a porous depletion layer is interposed between the inner face of each support of the enclosure structural and the second face of the mold functional element of conformation maintained vis-à-vis the inner face of the support.
By consuming in a depletion layer a fraction of the precursor gases of the gas phase before this does not reach the fibrous preform, the quantity of deposited matrix is decreased on the surface of the fiber preform, which avoids clogging rapid porosity on the surface of the preform and preserve more long a network of porosity allowing the gas phase of circulate to the heart of the preform. We obtain a deposit of more homogeneous matrix in the thickness of the preform limiting the deposit gradients in the preform.
The porous depletion layer may be in particular selected from one of the following textures: carbon mat, fabric two-dimensional carbon, carbon felt.
According to a second characteristic of the tooling of conformation of the invention, the supports and the mold elements of conformation are of a material selected from at least one of the materials graphite, carbon / carbon composite material (C / C) and ceramic matrix composite material (CMC).

4 The invention also relates to a load intended to be placed in a densification plant by chemical infiltration into vapor phase, said charge comprising a fibrous preform maintained in a conformation tool according to the invention.
As indicated above, such a loading made with the conformation tooling of the invention makes it possible not only to consolidate or densify a preform with a matrix deposit and / or more homogeneous interphase but also to avoid the formation of local overthicknesses or pustules on the surface of the preform.
According to a particular aspect of the loading of the invention, the Fiber preform is an aerospace engine part preform.
The invention also relates to an assembly comprising a part of a densification plant by chemical infiltration in phase gaseous fibrous preform having a reaction chamber, a reactive gas inlet pipe at a first end of the chamber and opening into a preheating zone, and a vent pipe located near a second end, and on the other hand at least one load according to the invention located in the room of the installation.
The subject of the invention is also a method of manufacturing a composite material part comprising:
the placement of a fibrous preform in a tool of conformation according to the invention, the consolidation of the porous preform by infiltration chemical phase of a matrix, - densification of the consolidated preform.
Brief description of the drawings Other features and advantages of the invention will emerge of the following description of particular embodiments of the invention, given by way of non-limiting examples, with reference to the attached drawings, in which:
FIG. 1 is an exploded diagrammatic view showing the mounting and loading a conformation tool with a fibrous preform according to one embodiment of the invention;

FIG. 2 is a view from above of the tool of FIG. 1 once mounted;
FIG. 3 is a sectional view according to the reference III of FIG.
the tool of Figure 2;

5 - the figure 4 is a sectional view according to the reference DI of the tool of Figure 2;
FIG. 5 illustrates an alternative embodiment of an element of conformation mold;
FIG. 6 is a schematic perspective view of a densification plant by chemical vapor infiltration comprising a load constituted by the tooling and the preform fibrous of Figure 1.
Detailed Description of Embodiment The present invention applies to the manufacture of parts made of composite material and in particular composite material thermostructural. More particularly, the invention finds an application advantageous during the consolidation and / or densification steps by chemical vapor infiltration of fibrous preforms.
Figure 1. shows the realization of a load comprising the placing a fibrous preform 10 in a tool of conformation 100 according to one embodiment of the invention.
Once completed, the loading is intended to be introduced into a reaction chamber of an industrial chemical infiltration plant in the gas phase. In the example described here, the tooling 100 is intended for receive fibrous preforms in the form of plates intended to in particular the characterization of composite materials. Tooling conformation of the invention can be used to receive and conform fibrous preforms for the production of shaped pieces various, such as vanes or movable nozzle flaps of aeronautical engines.
The fibrous preform 10 corresponds to a fibrous texture dry, that is to say not impregnated with a resin or the like. The texture fiber may be of various kinds, in particular fibers ceramic (for example silicon carbide) or carbon. The texture

6 fibrous used can be of various natures and forms such as especially:
- two-dimensional fabric (2D), - three-dimensional fabric (3D) obtained by 3D weaving or multilayer as described in particular in the WO document 2010/061140 and whose contents are incorporated herein by reference, - braid, - knit, - felt, - unidirectional layer (UD) of wires or cables multidirectional (nD) obtained by superposition of several UD sheets in different directions and binding the UD webs together by example by sewing, by chemical bonding agent or by needling.
It is also possible to use a fibrous structure formed of several layers of fabric, braid, knit, felt, tablecloths, cables or others, which layers are linked together, for example by sewing, by implantation of threads or rigid elements or by needling.
The conformation tooling 100 comprises an enclosure structure formed here of a first support 140 and a second support 170. The first support 140 comprises a first multi-perforated zone 141 having a plurality of perforations 1410 traversing the first support in its thickness, the multiperforated zone 141 being surrounded by a rim 142.
The second support 170 includes a second zone multipunched material 171 having a plurality of perforations 1710 crossing the second support in its thickness, the multiperforated zone 171 being surrounded by a ledge 172.
According to the invention, the conformation tooling 100 also includes a first mold functional element of conformation 120 and a second mold functional element of conformation 150. The first mold functional element of conformation 120 is intended to be housed in a first disbursed zone 143 present on the inner face 140a of the first support 140 and including the first multiperforated zone 141, the first functional element of conformation mold 120 resting on the rim 142 which allows maintain this element at a distance from the internal face 140a of the first

7 support 140 (FIGS. 3 and 4). The second functional element of mold conformation 150 is intended to be housed in a second zone disbursed 173 present on the inner face 170a of the second support 170 and including the second multiperforated zone 171, the second element shaping mold functional 150 resting on the ledge 172 which makes it possible to keep this element at a distance from the inner face 170a of the second support 170 (Figures 3 and 4). The first and second elements 120 and 150 conformation mold functional units each comprise a first face 120a, respectively 150a, having a predetermined shape .. corresponding to a piece shape to achieve, here a plate. The first conformation mold functional element 120 has a second face 120b intended to be held opposite the face internal 140a of the first support 140 at the first zone disbursed 143 by the rim 142 while the second element functional mold 150 has a second face 150b intended to be held opposite the internal face 170a of the second support 170 at the second disbursed zone 173 by the flange 172. The first and second mold functional elements of conformation 120 and 150 comprise a plurality of perforations 121 and 151.
According to the invention, the number, the size and / or the geometry of the perforations 121 and 151 present respectively on the first and second conformational mold functional elements 120 and 150 differ in relation to the number, size and / or geometry of perforations present on the support vis-à-vis. In the example described here, the first conformational mold functional element 120 has a greater number of perforations than the number of perforations 1410 present on the first support 140. Similarly, the second conformational mold functional element 150 has a greater number of perforations 151 than the number of perforations 1710 present on the second support 170. This makes it possible to increase the number of entry points of the gas phase into the fibrous texture and to split the incoming gas phase by perforations 1410 and 1710 supports 140 and 170 before coming into contact with the preform fibrous. This limits local overthicknesses and gradients

8 thicknesses of deposit in the thickness of the part to be consolidated or the formation of pustules in the fibrous preform.
In addition, the perforations 121 and 151 are preferably positioned respectively on the first and second elements conformational mold functionalities 120 and 150 in a staggered manner by compared to the perforations 1410 and 1710 present respectively on the first and second supports 140 and 170 (Figures 3 and 4). This allows to further limit the occurrence of local overthickness and limit gradients of deposit thicknesses in the thickness of the part to be consolidated or the formation of pustules in the fibrous preform.
FIG. 5 illustrates an embodiment variant of an element conformation mold functional unit 200 having a plurality of perforations 201 of oblong shape. Other forms of perforations can be considered according to parameters related to the preform fibrous to be densified. In the case of the conformation mold 200, increases the overall surface of the perforations through which the fiber preform is exposed to precursor gases entering the tooling by the supports of the structural enclosure. We also limit in this case the appearance of local overthicknesses or pustules in the preform fibrous.
According to a particular aspect of the invention, a layer porous depletion can be interposed between a support of the structural enclosure and a conformation mold functional element.
In the example described here, a first porous depletion layer 130 is interposed between the inner face 140a of the first support 140 and the second face 120b of the first mold functional element conformation 120 kept away from the inner face 140a by the edge 142 while a second depletion layer 160 is interposed between the inner face 170a of the second support 170 and the second face 150b of the second mold functional element of conformation 150 kept away from the inner face 170a by the flange 172. Porous depletion layers 130 and 160 allow to pre-consume some of the precursor gases of the gas phase entering through the performances 141 and 171 of the supports 140 and 170. The gradients of matrix deposits in the preform are thus limited fibrous. Indeed, by consuming a fraction of the precursor gases of the

9 gas phase before it reaches the fiber preform, decreases the amount of matrix deposited on the surface of the preform fibrous, which avoids a rapid clogging of the porosity in surface of the preform and preserve longer a network of porosity allowing the gas phase to circulate to the heart of the preform. A more homogeneous matrix deposit is thus obtained in the thickness of the preform limiting the gradients of deposit in the preform. Porous depletion layers can be made from two-dimensional fibers silicon carbide (SiC) or carbon fiber felts.
The supports forming the structural enclosure as well as the Functional elements of conformation mold can be realized in particular in graphite or in other materials able to withstand temperatures encountered during consolidation operations or chemical densification in the gas phase such as materials carbon / carbon or ceramic matrix (CMC) composites as per example of C / SiC materials (carbon fiber reinforcement densified by a silicon carbide matrix) or SiC / SiC (reinforcement and carbide matrix of silicon).
In the example described here, the fiber preform 10 is a preform obtained by three-dimensional weaving of type II SiC fibers.
Nicalon Type S.
The fibrous preform 10 is placed in the tooling of conformation 100 (FIGS. 3 and 4) with a view to its consolidation by chemical vapor infiltration. Tooling is closed by tightening members here constituted by screws 101 and nut 102, spacers 105 being used to adjust the fit between the two supports 140 and 170. The fiber preform 10 and the tooling 100 constitute a load 200 which is placed in an infiltration installation or oven chemical vapor phase 500 illustrated in Figure 6. In known manner per se, the chemical vapor infiltration installation 500 comprises a cylindrical enclosure 501 delimiting a reaction chamber 510 closed in its upper part by a removable cover 520 provided a gas intake pipe 521 which opens into a zone of preheating 522 for heating the gas before its diffusion in the reaction chamber 510 containing the preform (s) to be densified. The residual gases are extracted at the bottom 530 of the installation by a vent pipe 531 which is connected to suction means (no shown). The bottom 530 comprises a support 532 on which the loading 200 is intended to be deposited.
5 Heating in the preheating zone as well as inside the reaction chamber 510 is produced by a graphite susceptor 511 forming an armature electromagnetically coupled with an inductor (no represent). The space present in the reaction chamber 510 between the preheating zone 522 and the support 532 corresponds to the volume of

10 loading useful 512 of the infiltration installation 500, that is to say the volume available for loading fibrous preforms to be densified.
The preform 10 is consolidated by chemical infiltration in phase gas. In order to ensure the consolidation of the preform, a reactive gas containing at least one or more precursors of the matrix material to be deposited is introduced into the reaction chamber 510. In the case of a ceramic material, as here silicon carbide (SIC), one can use, as is well known per se, of methyltrichlorosilane (MTS) as a as precursor of SiC. In the case of carbon, for example, gaseous hydrocarbon compounds, typically propane, methane or a mixture of both. The consolidation of the porous preform is assured, in a manner well known per se, by depositing within it material of the matrix produced by decomposition of the precursor (s) contained in the reactive gas diffusing inside the internal porosity accessible from the preform. Pressure and temperature conditions necessary to obtain deposits of various matrices by infiltration chemical vapor phase are well known in themselves. A
pressure gradient is established between supply line 521 and the evacuation pipe 531 to promote the passage of gas flows reagent in the preform.
Consolidation tests of a fibrous preform with a conformation tooling according to the invention and of the same type as tooling 100 previously described has been realized. More specifically, for these tests the following elements were used:
- preform obtained by three-dimensional weaving of fibers SIC Hi-NicalonC) Type S, the preform having a plate shape,

11 first and second supports of the conformation tooling having in their multiperforated zone perforations having a diameter of 10 mm (phi 10 mm), the perforations being spaced apart others in a center-to-center step of 20 mm, first and second mold functional elements of conformation with perforations with a diameter of 5 mm (phi 5 mm) and spaced from each other in a center-to-center 8 mm, - porous layer of impoverishment interposed between each support of the conformation tooling and each mold element of conformation, each layer being made from a felt constituted of an entanglement of graphite fibers marketed by the company Le Carbone Lorraine, under the reference RVG 2000.
The preform was consolidated by chemical infiltration in phase gaseous phase of BN and SIC.
These tests showed a decrease in the thickness gradient deposition, in the thickness of the part, by a factor of 5 in comparison with conformation tooling of the prior art. In addition, the gradients deposit thickness, on the part surface, between an area directly exposed to the gas (zone of the preform vis-à-vis a perforation of a conformation mold functional element) and a masked area (zone of the preform located between two perforations of an element conformational mold functional) were decreased by a factor of 5 to 8 in comparison with a conformation tooling of the prior art.

Claims (8)

12 1. Conforming tooling (100) for chemical infiltration into vapor phase of a fibrous preform, the tooling comprising a structural enclosure formed of at least a first support (140) having a first multiperforated zone (141) and a second support (170) having a second multiperforated zone (171), the first and second supports being held against each other, characterized in that the first support (140) comprises on its inner face (140a) a first disbursed zone (143) including the first zone, multi-perforated (141), in that the second support (170) has on its inner face (170a) a second disbursed area (173) including the second multiperforated zone (172), and in that the tooling of conformation (100) further comprises at least first and second conformation mold functional elements (120, 150) present respectively in the first and second disbursed areas (143, 173) first and second supports (140, 170), each functional element shaping mold having a first face (120a; 150a) having a specific shape corresponding to a piece shape to realize and a second face (120b; 150b) maintained vis-à-vis the inner face of a support, each mold functional element of conformation having a plurality of perforations (121; 151) and having at least a number of perforations, a size of perforations or a geometry of perforations different from the number, size or geometry of the perforations present on the support vis-à-vis. 2. Tooling according to claim 1, wherein a layer of porous depletion (130; 160) is interposed between the face internal support of each support (140; 170) of the structural enclosure and the second face of the conformation mold functional element (120;
150) held in relation to the inner face of the support. 3. Tooling according to claim 2, wherein the layer porous depletion is selected from one of the following textures:
carbon mat, two-dimensional carbon fabric, carbon felt. 4. Tooling according to any one of claims 1 to 3, in which the supports (140, 170) and the functional elements of shaping mold (120, 150) are of a material selected from minus one of the following materials: graphite, composite material carbon / carbon (C / C) and ceramic matrix composite material (CMC). 5. Loading (200) to be placed in an installation densification method by chemical vapor infiltration (500), said loading comprising a fibrous preform (10) maintained in a conformation tooling (100) according to any one of the claims 1 to 4. 6. Loading according to claim 5, wherein the preform fibrous is an aeronautical engine part preform. 7. Assembly comprising a densification plant for chemical vapor infiltration (500) of a fibrous preform, having a reaction chamber (510), an intake pipe of reactive gas (521) at a first end of the chamber and opening into a preheating zone (522), and driving evacuation device (531) located near a second end, the assembly further comprising at least one load (200) according to the Claim 5 or 6 located in the chamber. 8. Process for manufacturing a composite material part comprising:
the placement of a fibrous preform (10) in a tool conformation (100) according to any one of Claims 1 to 4, the consolidation of the porous preform by infiltration chemical phase of a matrix, - densification of the consolidated preform.